ES2851500T3 - Matting agent and manufacturing method - Google Patents

Abstract

Matting agent for the preparation of matt pigmented surfaces, comprising agglomerates of inorganic pigment particles, characterized in that the inorganic pigment particles have a mean particle size d50 of 100 to 1000 nm, preferably 200 to 500 nm, the agglomerates have a average agglomerate size d50 from 2 to 200 µm, preferably from 2 to 100 µm, particularly preferably from 2 to 50 µm and most preferably from 2 to 20 µm and a specific surface area (BET) from 5 to 50 m2/ g.

Description

DESCRIPTION

Matting agent and manufacturing method

Field of Invention

The invention is directed to matting agents comprising agglomerates of inorganic pigment particles, to a method of manufacturing this type of matting agents, as well as to coating formulations, which contain the matting agents described herein. The present invention furthermore relates to plastic material containing these matting agents, to pigmented matte surfaces and to the use of agglomerates of inorganic pigment particles for matting pigmented coatings.

Technological Background of the Invention

Surfaces of plastic materials, laminates, and coatings such as lacquers and printing inks are commonly matted by precise micro-range roughening. The light striking the rough surface is therefore reflected in a non-directed way, but rather diffusely scattered. The height, shape and quantity of the surface structures determine the degree of gloss of the coating, of the lacquer film or of the printing ink.

To achieve a matt surface, special matting agents are usually added. This type of matting agents are, for example, spherical particles with a particle size in the range of 1 to 20 gm depending on the thickness of the film layer. Other common matting agents are based on precipitated or pyrogenated silicic acids, as well as on silica gels, but also on duromers, waxes or thermoplastic materials. The suitability of silicates, such as diatomaceous earth and calcined kaolin, as well as calcium carbonate and different types of hollow spheres, is also known.

Document EP 1398301 B1 discloses matting agents for paints and lacquers that are based on precipitated silicic acids, which have particle sizes (d50) in the range of 5 to 15 gm and a specific surface area (BET) (Brunauer, Emmett and Teller ) from 350 to 550 m2 / g. The silicic acids are optionally coated with wax.

DE 195 16 253 A1 also describes matting agents based on spray dried silica gel. To ensure sufficient stability of the aggregates, a binding agent such as layered silicate, pyrogenic silicon dioxide or organic polymer is used. In this case, the agent has a particle size of 1 to 20 gm and a specific pore volume of 0.4 to 2.5 ml / g.

JP 2002-338896 discloses a matting agent, which comprises particles with a certain distribution width and pore size.

Another approach to achieving matte surfaces is pursued by US 2015/0044441, which describes a sheet with at least two layers for bonding a surface. One of the layers, which is applied directly to the surface of the substrate to be glued, has adhesive properties, the outer layer presenting a matting agent. The agent can be, inter alia, titanium dioxide and silicon dioxide and have a preferred diameter of 2.0 to 6.0 gm.

Finally DE 1 519 232 A1 discloses a matte coating, which contains pigment agglomerates, which are prepared by spray drying and final tempering of commercial pigments together with sodium silicate as a binding agent. The agglomerates have a diameter of 2 to 70 gm.

Titanium dioxide aggregates with high mechanical strength are used in various technical fields. Document DE 102011 087385 describes the use of this type of aggregates with a d50 size of 5 to 100 gm as catalyst and catalyst support, the aggregates comprising particles with a size of between 50 to 100 nm. Document US 6,413,490 B1 also discloses granules, which are used as catalyst support, but also in paints and which have an average size of 10 to 150 gm. The granules themselves comprise particles with a size of 21 nm.

Document WO 98/50472 discloses a titanium dioxide pigment, which is coated with fine inorganic particles of 7 to 35 nm in size, such as silicic acid or calcium carbonate, the inorganic particles not absorbing the incident light and not interacting with common components in end use. The pigment is incorporated into different polymers and is particularly advantageous for use in polymers with a high PVC content. US 2,721,787 discloses dust-free titanium dioxide aggregates with a diameter of 30 to 140 gm. These are used in ceramic frits.

Conventional matting agents are incorporated into coating formulations. These are applied on substrates to matt their surface. Due to the usual matting agents contained, the formulations have notable disadvantages during their preparation and handling. In this way, established agents tend among others, to the formation of dust. Furthermore, during incorporation into coating formulations, the agents are mechanically ground. This leads to a significant increase in the viscosity of the formulation, which makes preparation, handling, as well as processing difficult. In addition, coatings containing conventional matting agents are chemically unstable, prone to fouling, and have low abrasion resistance. This leads to rapid wear and unaesthetic appearance of the matted substrate surface.

For this reason, there is a need for a matting agent for matting pigmented surfaces, which at least partially overcomes the disadvantages of the state of the art.

Objective statement and brief description of the Invention

The invention is based on the technical objective of making available a matting agent for the production of pigmented matte surfaces, with which at least part of the disadvantages of the agents of the state of the art can be overcome.

The technical objective is solved by a matting agent for the manufacture of pigmented matte surfaces, which comprises agglomerates of inorganic pigment particles, characterized in that the agglomerates have an average agglomerate size d50 of 2 to 200 gm, preferably of 2 to 100 gm , particularly 2 to 50 gm and most preferably 2 to 20 gm and a specific surface area (BET) of 5 to 50 m2 / g.

The matting agent according to the invention has excellent matting properties. By incorporating the agent, the viscosity of the coating formulation changes imperceptibly, so that the formulation containing the agent can be easily prepared, handled, and used. Without wishing to be bound by a specific scientific theory, it is assumed that conventional matting agents, when incorporated, are mechanically ground into minute particles in the one-digit nanometer range. This results in a significant increase in the viscosity of the formulation. In contrast, agglomerates are used in the present invention, which comprise inorganic pigment particles in the average size range of 0.1 to 1 gm. Upon incorporation into the formulation, the agglomerates are ground to a reduced proportion into their inorganic pigment particles. These pigment particles do not, however, lead to a significant increase in viscosity and thus allow easy incorporation. The formulations can be applied and hardened on surfaces of any type. The titanium dioxide pigment particles and their coatings containing agglomerates have improved chemical resistance, resistance to abrasion and resistance to soiling compared to conventional coatings containing matting agents.

For this reason, the invention is directed in a first aspect to a matting agent for the manufacture of pigmented matte surfaces, the agent comprising agglomerates of inorganic pigment particles and the agglomerates being characterized in that they have an average agglomerate size d50 of 2 to 200 gm preferably 2 to 100 gm, particularly preferably 2 to 50 gm and most preferably 2 to 20 gm and a specific surface area (BET) of 5 to 50 m2 / g.

In another aspect the invention relates to a method of manufacturing such a matting agent, which comprises agglomerates of inorganic pigment particles and is characterized in that the inorganic pigment particles are agglomerated by granulation, sintering, compression molding or dispersion. and subsequent drying, preferably by dispersion and subsequent drying.

In another aspect the invention is directed to matting agents for the preparation of pigmented matte surfaces, which is characterized in that the matting agent can be obtained according to a method disclosed herein.

In another aspect the invention relates to a coating formulation for the preparation of pigmented matte surfaces, characterized in that the formulation comprises a matting agent described herein.

In yet another aspect the invention relates to a pigmented matte surface of a substrate, characterized in that the surface is coated with a coating formulation as described herein.

In another aspect, the invention is directed to a pigmented matte surface, which is characterized in that the pigmented matte surface is the surface of a plastic material, a laminate or a coating and on it a coating formulation is applied and cured according to with the invention.

In another aspect the invention relates to a plastic material, which comprises the matting agent according to the invention.

The invention finally relates in another aspect to the use of agglomerates of inorganic pigment particles for the matting of pigmented coatings, the use being characterized in that the agglomerates have an average agglomerate size d50 of 2 to 200 gm, preferably of 2 to 100 gm, particularly preferably 2 to 50 pm and most preferably 2 to 20 pm and a specific surface area (BET) of 5 to 50 m2 / g. Other advantageous embodiments of the invention are indicated in the subclaims.

Figures

Figure 1: scanning electron microscope image of the pigment according to the invention according to example 2a.

Figure 2: laser diffraction analysis of the pigments according to the invention according to examples 1a, 2a and 3a.

Figure 3: laser diffraction analysis of pigments according to example 1a and comparison example 1.

Description of the Invention

This and other aspects, features, and advantages of the invention are apparent to the skilled person from a study of the following detailed description and claims. In this regard, each feature of one aspect of the invention may be used in any other aspect of the invention. It is also clear from this that the examples contained herein describe and are to illustrate the invention, but do not limit it, and in particular the invention is not limited to these examples. Numerical ranges, which are indicated in the format "from x to y", include the named values, as well as the values, which are in the range of the respective measurement accuracy known to the expert. When several preferred numerical ranges are indicated in this format, it is clear that all ranges, which result from the combination of the different end points, are also collected.

All indications of percentages, which are made in relation to the compositions described herein, refer, as long as the contrary is not explicitly stated, to% by weight, respectively referred to the corresponding mixture or composition.

"At least one", as used herein, means 1 or more, that is, 1, 2, 3, 4, 5, 6, 7, 8, 9 or more. Referring to a substance, the indication refers to the type of the substance and not to the absolute number of molecules. Together with the indications on weight, the indication refers to all compounds of the indicated type, which are contained in the matting agent, coating formulation, plastic material, etc., that is, that the matting agents, coating formulation, plastic material, etc., do not contain more than the indicated amount of the corresponding compounds, no more compounds of this type.

The mean agglomerate or particle size is understood in the context of the invention as the median based on the mass d50 (hereinafter: d50). The particle size distribution and mass median d50 were determined by laser diffraction as described herein.

"Pigment", as used herein, refers to inorganic or organic coloring agents practically not soluble in the medium of use according to DIN 55 943, which in the medium of use are not chemically or physically modified and maintain their structure particular. They are used for coloring, which is based on an interaction of pigment particles with visible light through absorption and remission. Pigment particles usually have a mean particle size (d50) in the range of 0.1 to 1 pm.

The matting agent described herein comprises agglomerates of inorganic pigment particles. These agglomerates have an average agglomerate size d50 of 2 to 200 pm, preferably 2 to 100 pm, particularly preferably 2 to 50 pm and most preferably 2 to 20 pm and a specific surface area (BET) of 5 at 50 m2 / g. The agglomerates preferably have a specific surface area (BET) of 10 to 30 m2 / g, particularly preferably 11 to 25 m2 / g and most preferably 13 to 20 m2 / g. The surface area was determined according to the static volumetric principle according to DIN 66 131. The coatings, which contain agglomerates with a low specific surface area, have a high resistance to fouling and are thus particularly advantageous when they are exposed to soiling. In particular for support surfaces, which come into contact with food and beverages such as tea or coffee, as interior and exterior furniture objects, this type of agglomerates with a reduced specific surface are suitable.

As inorganic pigment particles any inorganic pigment known in the state of the art and suitable for the purpose according to the invention can be used. Mixtures of different inorganic pigments can also be used.

The inorganic pigment according to the invention is preferably a metal salt and even more preferably a metal oxide. "Metal salt", as used herein, refers to the generally valid definition of this term and is a salt, which comprises at least one metal cation and at least one anion. "Metal oxide" as used herein refers to the generally valid definition of this term and is a compound, which comprises at least one metal atom and at least one oxygen atom.

Suitable inorganic pigments are, but are not limited to, white pigments, such as titanium dioxide (CI

Pigment White 6), Zinc White, Color Zinc Oxide; zinc sulfide, lithopone; black pigments, such as iron oxide black (C.I. Pigment Black 11), iron-manganese black, spinel black (C.I. Pigment Black 27); soot black (C.I. Pigment Black 7); color pigments, such as chromium oxide, chromium oxide hydrate green; chrome green (C.I. Pigment Green 48); cobalt green (C.I. Pigment Green 50); ultramarine green; cobalt blue (C.I. Pigment Blue 28 and 36; C.I. Pigment Blue 72); ultramarine blue; manganese blue; ultramarine violet; cobalt and manganese violet; iron oxide red (C.I. Pigment Red 101); cadmium sulfoselenide (C.I. Pigment Red 108); cerium sulfide (C.I. Pigment Red 265); molebdate red (C.I. Pigment Red 104); ultramarine red; iron oxide brown (CI Pigment Brown 6 and 7), mixed brown, spinel and corundum phases (CI Pigment Brown, 29, 31, 33, 34, 35, 37, 39 and 40), titanium chromium yellow (CI Pigment Brown 24), Chrome Orange; cerium sulfide (C.I. Pigment Orange 75); iron oxide yellow (C.I. Pigment Yellow 42); nickel titanium yellow (C.I. Pigment Yellow 53; C.I. Pigment Yellow 157, 158, 159, 160, 161, 162, 163, 164 and 189); chrome titanium yellow; spinel phases (C.I. Pigment Yellow 119); cadmium sulfide and zinc cadmium sulfide (C.I. Pigment Yellow 37 and 35); chromium yellow (C.I. Pigment Yellow 34), as well as bismuth vanadate (C.I. Pigment Yellow 184).

In addition, inorganic pigment particles, which are commonly used as bulking agents, such as aluminum oxide, aluminum hydroxide, zinc sulfide, natural and precipitated chalk and barium sulfate, can also be used.

The pigment particle is preferably selected from the group consisting of magnesium carbonate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, huntite, white lead, lithopon, cristobalite, kaolin, and mixtures thereof. The most preferred of all the pigment particles described herein is, due to its pigment properties, as well as its high hardness on the Mohs scale, titanium dioxide. Titanium dioxide can occur in this case in the rutile, anatase or brookite crystal structures, usually in the rutile or anatase crystal structure. Rutile is particularly suitable due to the reduced photolytic catalysis activity compared to anatase.

The inorganic pigment particle may furthermore be inorganically and / or organically post-treated. In this case the particle comes into contact with inorganic or organic substances. This type of substances and techniques are established in the state of the art. They are part of, among others, inorganic substances, silicon dioxide and aluminum oxide. In a preferred embodiment the particle is inorganically post-treated.

As already mentioned, titanium dioxide has been selected as the most preferred inorganic pigment particle. The titanium dioxide described herein may have been prepared according to the sulfate method or according to the chloride method. This is preferably selected from the group consisting of untreated titanium dioxide pigment, post-treated non-micronized titanium dioxide pigment, final titanium dioxide pigment, and mixtures thereof. "Post-treated", as used herein, refers to at least one additional method step, which is carried out after the pigment or pigment pigment is prepared. These types of method steps are well established in the state of the art. They include, for example, grinding by sand, layering the pigment or inorganic raw pigment, washing, drying, steam grinding or combinations of these steps. In the case of a conventional post-treatment, the raw pigment is first subjected to sand grinding, optional inorganic modification with silicon dioxide and aluminum oxide, washing, drying and finally grinding of steam. The after-treatment serves to improve the physical, in particular optical, and chemical properties of the particle pigment or agglomerate and can be adapted to the respective specific use of the finished pigment, for example of the respective coating formulation. In different embodiments, the titanium dioxide is post-treated with silicon dioxide and / or with aluminum oxide. In this way, the titanium dioxide can be post-treated first with silicon dioxide and then with aluminum oxide. This post-treatment, as well as substances and techniques, which are used for it, are well known in the state of the art. Post-treated pigments are also referred to in the prior art as finished pigments. "Untreated", as defined herein, consequently refers to the pigment particle or the raw pigment. Thus, titanium dioxide can be used according to the invention as a crude pigment after the sulfate method. This can be dried, preferably spray-dried or, if necessary, dispersed with a solvent before drying.

Particle size adjustment can occur by established methods, such as grinding, or by selecting certain conditions during pigment preparation.

The inorganic pigment particle preferably has a mean particle size d50 of from 100 to 1000 nm, particularly preferably from 200 to 500 nm.

The agglomerates furthermore have an oil absorption value, measured according to DIN ISO 787 part 5, preferably 15 to 25 g / 100 g, particularly preferably 17 to 22 g / 100 g.

The agglomerates according to the invention, of the inorganic pigment particles, can be prepared in according to any of the methods described in the state of the art. The inorganic pigment particles are preferably agglomerated by granulation, sintering, compression molding or dispersion with subsequent drying. The inorganic pigment particles are particularly preferably dispersed first and then dried. The dispersion can also be carried out according to all conventional methods, which are suitable for this. The pigment particles can be mixed with a dissolving agent for this, it being possible to use water, organic solvents or a mixture thereof. Suitable organic solvents are all organic solvents known in the state of the art and suitable for the purpose according to the invention, in particular polar protic and polar aprotic solvents. They include, but are not limited to, alcohols such as isopropanol, n-propanol, as well as acetone, ethyl acetate, ethylmethylketone, tetrahydrofuran (THF) and dimethylsulfoxide (DMSO). In addition, short-chain alkanes such as pentane or heptane can also be used. In addition, a customary dispersing agent such as commercially available Tegomer DA 640, trimethylolpropane (TMP), octyltrichlorosilane (OCTCS), octyltriethoxysilane (OCTEO) or etidronic acid can be added thereto. The dispersion can be carried out by usual methods and techniques, for example in a vessel equipped with a conventional stirrer unit. The dispersion of the pigment particles is preferably carried out in a stirrer bead mill. For this, for example zirconium oxide grinding beads with a size of 0.4 to 0.6 mm can be used and ground at a speed of 3000 rpm for 15 to 30 minutes in a circulatory manner.

The subsequent drying can be carried out with the aid of any method and technique known in the state of the art. Suitable for this are, but not limited to, belt dryers, floor dryers, rotary dryers and spray dryers. The dispersion is preferably dried by spray drying. Drying conditions are selected such that agglomerates in the size ranges described herein result. They can optionally be achieved by established drying methods, agglomerates with a narrower size distribution. The agglomerates can also be ground by standard techniques to achieve the sizes described herein. It is part of them, without being limited to it, grinding, for example, with an impact mill.

Matting agents that can be obtained according to the method described herein are also claimed.

Another object of the present invention are coating formulations for the preparation of pigmented matte surfaces, which contain the matting agents described herein. The agent may be contained in an amount of 0.1 to 98% by weight, preferably 1 to 50% by weight, particularly preferably 2 to 25% by weight and most preferably 3 to 23% by weight based on the total weight of the coating formulation, in the coating formulation. These formulations can optionally comprise pigment. In a preferred embodiment, these pigments have the same composition as the pigments of the agglomerates, in other words, the composition of the pigments and of the pigments of the agglomerates are identical. The formulation preferably furthermore does not have any additional non-agglomerated pigments.

The formulation may contain, in addition to the matting agent according to the invention, customary matting agents. The formulation preferably does not have additional matting agents.

The formulation preferably contains customary components. As a component, all components known in the state of the art can be used, which are suitable for the purpose according to the invention. The formulation preferably comprises at least one component selected from the group consisting of binding agent, defoaming agent, dispersing agent, bulking agent, solvent agent, preservative agent, auxiliary film-forming agent, as well as auxiliary rheology agents. Also common fungicidal preservatives are part of the preservatives. They are part of the formulations of coating, lacquers, paints and printing inks.

Another object of the present invention is a pigmented matte surface of a substrate, the surface being characterized in that this surface is coated with a coating formulation described herein. The formulations can be presented as 1-component, 2-component, and multi-component set lacquers in customary compositions. The lacquers are applied to the substrate by conventional techniques and methods and, depending on the composition of the lacquer, in particular the binding agent, are cured, for example by UV radiation or drying. They are part of the substrates, but are not limited to them, wood, plastic materials, metals, paper, glass fabric and mixtures of them.

Another object of the invention is a plastic material, which is characterized in that the plastic material comprises a matting agent according to the invention. As plastic material any plastic material known in the state of the art and suitable for the purpose according to the invention can be used. "Plastic material", as used herein, refers to a material, which contains at least 50% by weight of a polymer, based on the total weight of the plastic material. The polymer can be a homopolymer, a copolymer, or a graft polymer. The polymer can furthermore be atactically, isotactically or syndiotactically its polymer. The plastic material is furthermore a thermoplastic, an elastomer, a thermoset plastic or a thermoplastic elastomer, preferably a thermoplastic. The polymer is, but is not limited to, selected from the group consisting of polyolefins, polystyrene, polyamide, polyketone, polyester, polyurethane, poly (meth) acrylate, and mixtures thereof. Polyolefin is, without limitation, selected from the group consisting of polyethylene, polypropylene, polybutylene, as well as mixtures thereof. The matting agent can be incorporated by known techniques and methods into the plastic material, for example by extrusion. The matting agent is processed in the usual amounts in plastic material. The plastic material thus contained has 0.1 to 30% by weight, preferably 1 to 25% by weight of the agent according to the invention, based on the total weight of the plastic material.

Finally, another object of the invention is the use of agglomerates of inorganic pigment particles for the matting of pigmented coatings, characterized in that the agglomerates have an average agglomerate size d50 of 2 to 200 pm, preferably of 2 to 100 pm, so particularly preferably 2 to 50 pm and most preferably 2 to 20 pm and a specific surface area (BET) of 5 to 50 m2 / g.

In another embodiment of the invention, pigment mixtures can also be used as pigment compositions, in which, for example, a conventional pigment, which offers glossy surfaces, is mixed with pigment agglomerates.

The pigment composition according to the invention contains agglomerates of the inorganic pigment particles. In the finished coating, the pigment composition occurs both in the form of agglomerates of inorganic pigment particles, which take care of the desired surface roughness, and also in the form of well-dispersed inorganic pigment particles, which meet the requirements classics to be met by a pigment.

The invention is based on pigment composition in coatings such as lacquers, paints and printing inks, which function both as matting agents, as well as pigment, so that the use of an additional matting agent for the generation of matted surfaces can be eliminated. .

Test methods

Median and particle size distribution based on mass d50

The particle size distribution and the mass median d50 were determined by laser diffraction with the Mastersizer 2000 particle size analyzer from Malvern. For the measurement, a suspension of Calgon's solution (80 ml, 0.06% in distilled water) was dispersed with the particulate material to be examined (2 g) for 60 s with an Ultraturrax shaker at 9500 rpm.

The measurement was carried out in the following device settings:

Refractive index (n) mean (water): 1.33,

refractive index (n) of titanium dioxide (rutile): 2,741 (in red laser) and 2,960 (in blue light);

refractive index (n) of titanium dioxide (anatase): 2,550 (in red laser) and 2,500 (in blue light);

absorption index (k) of titanium dioxide (rutile): 0.08 (in red laser) and 0.08 (in blue light);

absorption index (k) of titanium dioxide (anatase): 0.07 (in red laser) and 0.08 (in blue light);

laser shading: 0.8%;

wavelength of light sources: red: 633 nm; blue: 466 nm.

Viscosity KE ( from German Krebs-Einheiten, Krebs units) ( drip viscosity)

The KE viscosity of the fresh lacquer was determined with a Krebs-Stormer viscometer (KU-2 viscometer) from Brookfield. The result is indicated in the Krebs unit.

Oil absorption

The amount of linseed oil is determined, which is required for the complete wetting of the particulate material to be examined (100 g). The method is carried out in accordance with DIN ISO 787 part 5.

Specific surface ( BET)

The BET surface is determined by measuring with a Tristar 3000 analyzer from Micromeritics in accordance with the static volumetric principle according to DIN 66131.

Examples

Example 1a

A titanium dioxide pigment base body in the rutile crystal modification was post-treated with ALO3, filtered, washed, separated and dried, however not micronized, and then kneaded again in water (3 , 25 l) giving rise to an aqueous suspension with TiO2 (2.5 kg). The suspension was dispersed in a Labstar stirrer bead mill (SiLi type ZY beads from 0.4 to 0.6 mm) for 16 minutes in a circulatory method with a specific energy input of 0.2 kWh / kg. The suspension was then dried in a spray drier (Büchi B-290 mini spray drier).

The spray dryer agglomerates had a d50 particle size of 10 gm, a specific surface area (BET) of 16 m2 / g and an oil absorption of 20 g / 100 g.

Example 1b

With the spray-dried pigment from Example 1a, an aqueous dispersion lacquer (pigment concentration-volume PVK 19%) was prepared according to the following standard:

First of all, a preliminary solution was prepared with the components according to table 1 and with the aid of a solvent. The premix (192.50 g) was then mixed with titanium dioxide pigment (57.50 g), which was obtained according to example 1a), in a Skandex mixer, adding glass beads (50 g of beads SiLi type S) for 30 minutes.

Table 1: previous solution

Component Quantity [g]

Water 36.50

Defoaming agent Agitan E255 1.00

Fungicide / algaecide Actizid MBS 0.50

Dispex CX4320 dispersing agent 2.50

Dispersing agent Edaplan 480 2.50

Thickening agent Rheolate 644 2.50

Binding agent_________ Acronal LR9014__________ 147.0

Sum 192.50

The viscosity KE (drip viscosity) was determined in the fresh lacquer mixture. For the determination of the gloss, an application was prepared on black-white contrasting cardboard and then the gloss was measured (20 °, 60 °, 85 °) with a Haze-Gloss reflectometer from the company Byk-Gardner. The measured data are derived from table 2.

Example 2a

Spray dryer agglomerates were prepared as in Example 1a, with the difference that Tegomer DA 640 dispersing agent (25 g) was added to the suspension in the stirrer bead mill.

The spray dryer agglomerates had a d50 particle size of 10 gm, a specific surface area (BET) of 13.8 m2 / g and an oil absorption of 19.6 g / 100 g.

Example 2b

An aqueous dispersion lacquer was prepared as in Example 1b and the KE viscosity as well as the gloss (20 °, 60 °, 85 °) were determined as in Example 1b. The measured data are derived from table 2.

Example 3a

Spray dryer agglomerates were prepared as in Example 2a, with the difference that the pigment was not kneaded again in water (3.25 L), but in ethanol / ethyl acetate (3.25 L, ratio 1, 6: 1).

The spray dryer agglomerates had a d50 particle size of 4 gm, a specific surface area (BET) of 13.5 m2 / g and an oil absorption of 20 g / 100 g.

Example 3b

An aqueous dispersion lacquer was prepared as in Example 1b and the KE viscosity as well as the gloss (20 °, 60 °, 85 °) were determined as in Example 1b. The measured data are derived from table 2.

Comparison example 1

Comparison Example 1 comprises the preparation of an aqueous dispersion lacquer, as described in Example 1b, having used instead of the spray-dried pigment according to Example 1a, a titanium dioxide pigment post-treated with ALO3 in the crystalline modification of rutile, under the trade name Kronos 2066 from KRONOS INTERNATIONAL, INC. Viscosity KE, as well as gloss (20 °, 60 °, 85 °) were determined as in example 1b. The measured data are derived from table 2.

Comparison example 2

Comparison Example 2 comprises the preparation of an aqueous dispersion lacquer, as described in Comparison Example 1, with the difference that the commercial matting agent Acematt TS100 was additionally added to the previous solution (see Table 1). (8.82 g, corresponding to 6% by weight based on binding agent). Viscosity KE as well as gloss (20 °, 60 °, 85 °) were determined as in example 1b. The measured data are derived from table 2.

Comparison example 3

Comparison Example 3 comprises the preparation of an aqueous dispersion lacquer, as described in Comparison Example 2, with the difference that Syloid W500 (8.82 g, corresponding to 6% by weight based on binding agent) was used as commercial matting agent. Viscosity KE, as well as gloss (20 °, 60 °, 85 °) were determined as in example 1b. The measured data are derived from table 2.

Table 2: aqueous dispersion lacquer

Gloss 20 ° Gloss 60 ° Gloss 85 ° Viscosity KE [Krebs]

Example 1b 0 14 21 120

Example 2b 0 10 12 119

Example 3b 8 42 68 122

Comparison example 1 47 75 95 121

Comparison example 2 26 64 88 140

Comparison example 3 11 52 76 127

The lacquers prepared according to the invention (examples 1b, 2b, 3b) have compared to the comparison lacquers, which were prepared with commercial titanium dioxide pigment and additionally 6% by weight of commercial matting agent (comparison examples 2, 3), a higher degree of matting (lower gloss) and a lower viscosity (KE viscosity). With respect to the gloss lacquer, prepared with commercial titanium dioxide, which does not contain a matting agent (comparison example 1), the matte lacquers prepared according to the invention (examples 1b, 2b, 3b) do not show any significant increase in the viscosity (KE viscosity).

Claims (14)

1. Matting agent for the preparation of pigmented matte surfaces, comprising agglomerates of inorganic pigment particles, characterized in that the inorganic pigment particles have an average particle size d50 of 100 to 1000 nm, preferably 200 to 500 nm, the agglomerates have a mean agglomerate size d50 of 2 to 200 gm, preferably 2 to 100 gm, particularly preferably 2 to 50 gm and most preferably 2 to 20 gm and a specific surface area (BET) of 5 to 50 m2 / g. 2. Matting agent according to claim 1, characterized in that the inorganic pigment particles are a metal salt. Matting agent according to claim 2, characterized in that the metal salt is a metal oxide. Matting agent according to one or more of Claims 1 to 3, characterized in that the metal oxide is titanium dioxide; and / or the titanium dioxide is selected from the group consisting of untreated titanium dioxide pigment, post-treated non-micronized titanium dioxide pigment, final titanium dioxide pigment, and mixtures thereof; and / or the agglomerates have a specific surface area (BET) of 10 to 30 m2 / g, preferably 11 to 25 m2 / g, and particularly preferably 13 to 20 m2 / g; and / or the agglomerates have an oil absorption value, measured according to DIN ISO 787 part 5, of 15 to 25 g / 100 g, preferably 17 to 22 g / 100 g. 5. Manufacturing method of a matting agent comprising agglomerates of inorganic pigment particles, characterized in that the inorganic pigment particles, which have a mean particle size d50 of 100 to 1000 nm, preferably 200 to 500 nm, agglomerate by granulation, sintering, compression molding or dispersion, with subsequent drying, preferably by dispersion with subsequent drying. 6. Method according to claim 5, characterized in that the dispersion of the inorganic pigment particles is carried out in a stirrer sphere mill to obtain a dispersion, and / or the drying of the dispersion is carried out by drying by means of spray. Method according to claim 5 or 6, characterized in that during dispersion at least one component selected from the group consisting of water, organic solvent agent and dispersing agent is used. Method according to claim 5 to 7, characterized in that the inorganic pigment particles are a metal salt, preferably a metal oxide and even more preferably titanium dioxide, and / or titanium dioxide is selected from the group consisting of untreated titanium dioxide pigment, post-treated non-micronized titanium dioxide pigment, final titanium dioxide pigment, and mixtures thereof. Coating formulation for the preparation of pigmented matte surfaces, characterized in that the formulation comprises a matting agent according to one or more of claims 1 to 4. Coating formulation according to claim 9, characterized in that the formulation comprises non-agglomerated inorganic pigment particles, selected from the group consisting of untreated titanium dioxide pigment, post-treated non-micronized titanium dioxide pigment, final dioxide pigment titanium and mixtures of them. Coating formulation according to claim 9 or 10, characterized in that the formulation does not comprise any additional matting agent; and / or the formulation does not comprise any additional non-agglomerated pigments; and / or the formulation comprises at least one component selected from the group consisting of binding agent, defoaming agent, dispersing agent, bulking agent, solvent agent, preservative agent, auxiliary film-forming agent and auxiliary rheology agent. 12. A pigmented matte surface of a substrate, characterized in that the surface is coated with a coating formulation according to one or more of claims 9 to 11. 13. Plastic material comprising a matting agent, characterized in that the plastic material comprises a matting agent according to one or more of claims 1 to 4. 14. Use of agglomerates of inorganic pigment particles for the matting of pigmented coatings, characterized in that the inorganic pigment particles have a mean particle size d50 of 100 to 1000 nm, preferably 200 to 500 nm, the agglomerates have a size average agglomerate d50 2 to 200 gm, preferably 2 to 100 gm, particularly preferably 2 to 50 gm and most preferably 2 to 20 gm and a specific surface area (BET) of 5 to 50 m2 / g .